In recent years, the development of the liquid-crystal television of a portable type using the liquid-crystal matrix panel is actively performed, the details are introduced at page 211 through page 240 of, for example, "Nikkei Electronic No. 351" (issued Sept. 10, 1984).
One example of the electrode circuit diagram of the active matrix panel using TFT (thin film transistor) in the liquid-crystal television is shown in FIG. 11. In FIG. 11 segment electrodes (1), (1) are formed on the first base plate, the TFTs (thin film transistor) (2), (2) are formed on the first base plate, corresponding to the respective segment electrodes (1), (1) and the TFTs, are connected with the segment electrodes (1) at the sources of the TFTs (2). Drain lines (3) are connected with the drains for each of the columns of the TFT (2) corresponding to the segment electrodes (1) of the column direction, gate lines (4) are connected with the gates for each of the rows of the TFT (2) corresponding to the segment electrodes (1) of the row direction.
A common electrode (5) is formed on the second base plate opposite to the first base plate with each of the segment electrodes (1), the TFTs (2) the drain lines (3), the gate lines (4) being formed thereon. The liquid crystal is filled between the first, second base plates.
The number of the rows, i.e., the number of the gate lines (4) is 240, corresponds to approximately the number of effective scanning lines among the number of the scanning lines 262.5 of one field of the NISC system.
Thus, all the 240 are used respectively in the odd-number field and the even-number field during the driving operation, the same element is driven after 1/60 seconds.
Picture signals are applied upon the drain lines (3) of the active matrix panel, and when the liquid crystal is normally driven, the AC driving is preferable, namely, the polarity of the signal is desired to be inverted at a given period through the consideration of the durability or the like when the liquid crystal is normally driven, with the picture signal becoming like, for example, FIG. 12.
Namely, assume that the nth of the odd-number field is On, the nth of the even-number field is En, the polarity is reversed for each of the fields as the odd-number fields (01), (02) become positive in polarity, the even-number fields (E1), (E2) become negative in polarity.
Thus, the period by which the same element is driven by the same polarity becomes 1/30 seconds, i.e., one frame period. Accordingly, the flicker (flitting) on the picture face by the polarity reversion is hardly conspicuous.
However, in the above-described conventional example, the number of the rows is 240 with the number of the picture elements being limited, thus providing the picture face comparatively low in resolving degree.
Thus, the method of improving the picture quality is proposed with the number of the picture elements being increased such as 480 in the number of the rows.
The electrode circuit diagram of the active matrix panel in the second conventional embodiment is shown in FIG. 13, the same numerals are given to the same portions as those of FIG. 11 to omit the description.
The gate lines (41), (42) . . . in FIG. 13 are 480, are respectively taken out to the left, and to the right for each of the rows, the gate signals are applied upon the gate line (41) . . . in the odd-number field, the gate signals are applied upon the gate line (42) . . . in the even-number field.
The picture signals to be applied upon the drain lines (3), (3) of the active matrix panel are reversed in polarity for each two-fields as shown in FIG. 14, so that the period by which the same element is driven by the same polarity becomes 1/15 seconds, namely, the two-frame period.
Thus, the flickers on the picture face by the polarity reversion became low in frequency, which was a very conspicuous defect.
It is to be noted that the flickers are caused at the one-frame period as shown in FIG. 15(b) with respect to the driving waveform of the two-frame period shown in FIG. 15(a) when the LCD panel (1) is seen from the front face, but the brilliance is reduced as shown in FIG. 15(c) in a case where 10.degree. is deviated from, for example, the front face when the LCD panel (1) is obliquely seen, the period of the flicker becomes also the two-frame period to make the flicker more conspicuous.